The superior colliculus recevies spatially ordered visual information from the retina and visual cortex. This information undergoes a spatial transformation in collicular networks and is relayed to brainstem and thalamic structures implicated in the control of eye movements. This research investigates the nature of the spatial transformation which the colliculus imposes on retinofugal and corticofugal visual information with particular emphasis on the sensorimotor aspects of this transformation. Single unit recordings, focal electrical stimulation, eye movement measurements and receptive field mapping techniques are used to assess the hypothesis that collicular cells with large receptive fields reformat visual spatial information to suit the functional organization of the oculomotor system. Since large numbers of collicular cells must function together in this task, the hypothesis requires that the colliculus convert a retinotopic position code to an ensemble code of visual space.